The present invention relates generally to shock-absorbing devices and, more specifically, to a shock-absorbing device capable of dampening bi-directional forces and method therefor. The present invention is particularly useful in, although not strictly limited to, marine applications desiring reduction of water motions such as mooring lines for floating docks and boats.
The increasing popularity of water sports and activities has dramatically affected the number of individuals making use of coastal and inland waters such as lakes, inlets and canals. A direct result is increased watercraft traffic and artificially generated wake. These wakes alone or in combination with the natural wind and wave action created by various weather conditions, create annoying conditions for water enthusiasts recreating on floating docks. In addition, tumultuous water conditions resulting in uncontrolled dock movements can cause damage to moored docks as well as personal injury.
Several attempts have been made to design a suitable and effective device for attenuating dock movement in response to waves. Examples of such devices may be found by reference to U.S. Pat. No. 4,955,309 to Ciccone, U.S. Pat. No. 5,307,753 to Besonen, Sr. et al., U.S. Pat. No. 5,524,566 to Rapa et al., U.S. Pat. No. 5,694,879 to Taylor, and U.S. Pat. No. 5,832,861 to Taylor. However, in view of the present invention, these patents are disadvantageous.
For instance, the configuration of U.S. Pat. No. 4,955,309 consists of a tubular housing, a concentric plunger member, and a resilient coiled compression spring. A disadvantage of this design is the uneven dampening that occurs from only one plunger member acting on the spring. Even if another plunger and spring combination were added to receive opposing forces, the uneven dampening effect would remain as a product of the independence of the plungers and springs.
Another configuration, described in U.S. Pat. No. 5,524,566, incorporates an automobile shock absorber in place of a compression spring in an effort to eliminate resonance. This change, while it may alleviate some minimal sounds, does not alleviate the potentially dramatic uneven dampening effect that occurs from a one-sided plunger/damper setup.
The alternative device of U.S. Pat. No. 5,832,861 describes a multi-spring unit with self-described dynamic load transferring characteristics resulting from forces causing one spring to extend and an identical counterpart to compress. One disadvantage of this design is that the compressed size of the partner spring limits the extension of the extension spring.
U.S. Pat. No. 5,307,753 teaches an extension-biasing member in place of a compression spring. A disadvantage inherent in the use of an extension-biasing member is that the device is pulled by the wave action in the same direction as the spring extends. With large forces, the inner cord may snap thereby overextending the spring, destructively affecting the elasticity.
Therefore, it is readily apparent that there is a need for a dampening device wherein two independent rods receive opposing forces and compress the respective ends of a coiled spring thereby providing a balanced, bi-directional dampening affect and thus preventing the above-discussed disadvantages.
Briefly described, in a preferred embodiment, the present invention overcomes the above-mentioned disadvantages, and meets the recognized need for such a device, by providing a bi-directional dampening device wherein two independent rods, one associated preferably with a dock and the other with a fixed object, receive forces from the raising and lowering of the dock and transfer these forces to the respective ends of a coiled spring thereby providing a bi-directional dampening affect.
According to its major aspects and broadly stated, the present invention is a dampening device having two independent rods attached at distal ends to securing plates wherein forces on the rod are transferred to the respective ends of the spring and dampened thereby.
More specifically, the present invention is a dampening device with two independent rods positioned inside a heavy-duty spring. A support plate is positioned on each end of the spring, wherein the distal end of each rod is secured to the respective plate, and wherein the proximal ends of each rod extend through a throughhole in the respective plate and is allowed to slide therethrough. An eyebolt member is attached to each proximal end of each rod for securing a cable therethrough, with one cable secured to a dock and the other cable secured to a fixed object. As the dock raises and lowers in response to water conditions, the shock device receives and transfers the forces to the respective ends of the heavy-duty coiled spring thereby compressing the spring and providing a balanced, bi-directional dampening affect.
A feature and advantage of the present invention is the ability of such a device to provide a bi-directional shock absorber that is simple in construction and thus easy to manufacture.
A feature and advantage of the present invention is the ability of such a device to provide a balanced bi-directional dampening effect.
A feature and advantage of the present invention is the ability of one heavy-duty coiled spring to receive and dampen forces from two independent and opposing rods.
A feature and advantage of the present invention is the ability of a heavy-duty coiled spring compression device to limit and maintain the distance between a moored object and an anchoring device.
These and other objects, features and advantages of the invention will become more apparent to one skilled in the art from the following description and claims when read in light of the accompanying drawings.